Aldal condensation



Patented Dec. 29, 1953 UN-lTED STATES PATENT oFFics l V I --l)oyvden,Norton-on-T ees,

England, assignors to Imperial Chemical Industries'llinii ted, a cor-,lif atitlil Of Great Blitaili No Drawing. Ap lication June 14; 1950,Serial No.- 168,174 dlaiiiispi'iority, application Great Britain Jllfl30, 1949 Glaiin's. (o1. zen-.594) i 'riiis invention relatesto organichyd -y coin r und It is known to producealdol condensation prod uctsfrom carbonyl compounds, in particular'diacetone alcohol from acetone,by contacting the carbonyl compounds in the liquid state. with granularcondensation catalysts comprising a basic hydroxide, oxide-carbonate oroicy'chloride of a metal of group II of the periodic table and there has'beenfdisclo'sed among others-acatalyst produced, by mixing hydratedlime, Portland cemerit, fkieselguhr, sodium hydroxide, "and water into apas'te and granulating. However, we have found that this process is notentirely s'atisfac cry, s'ince the "reaction velocity is'rather low andthe "catalyst life is short. i According" to the present invention aldolcondensation products are produced from carbonyl compounds by bringingthe carbonyl compound into contact in the liquid phase at a moderatetemperature with a catalyst comprising calcium oxide, calcium hydroxide,hydrous calcium oxide or hydrous calcium hydroxide, supported on alithiaalumina complex analogous to "sodiumbeta-alumina and to thespinels with a defective 1attice. v j The process is of grea'test valuein relation to theproduction of (ii-acetone alcohol from acetone.D'i-acetone alcohol is user-c1 as a solvent for nitrocellulose,cellulose acetate and many natural and synthetic resins, e. g., rosin,ester gum, kauri, copal and some alkyd andrphenolic resins.

In producing di-acetone from acetone according to the invention the eperature should not exceed 30 C. since above this temperature theequilibrium concentration of di-acetone alcohol in the mixture is so lowthat the process becomes uneconomic. While temperature of from 0 C. to30 C. are suitable, it is preferred on account of the greater reactionvelocity achieved to employ a temperature of C. to 0., especially about20 C.

The process may be conducted in conventional apparatus, for example bypassing the liquid carbonyl compound through a bed, or number of beds,of catalyst contained in a reactor which is preferably provided with ajacket and/or coils through which a temperature controlling medium ispassed. To reduce pressure drop and minimize catalyst carry-over in theproduct it is preferred to use a granular catalyst.

The process may be operated batchwise or continuously. It is preferredto operate continuously. When operating continuously a suitable liquidspace velocity is up to 1 litre per litre of tulle catalyst volume perhour. one method is-toeinploy a high space velocity and to recycle atleast a portion of the l roduct to the reaction zone. In this way a highoutput is obtained. We have found that most frequently a liquid spacevelocity of "about 0.5 litre/litre of 'bulk catalyst volume per hour ispreferable;

The di-acetonealcohol may be separated from the product by flashgdistillations, whereby the bulk of the acetone isremovdas distillate,followed by fractional distillation of the bottom product under reducedpressure.

It is preferred to operate so that the catalyst is immersed in liquid,since if the liquid emi trickles over the catalyst there is poorc'ont'ac't and lower efliciency. Satisfactory workingis accomplished byfeeding the liquid to the top of a reactor and controlling the rate ofwithdrawal from the bottom thereof .by means of a cock,.so that thecatalyst is always covered.

The lithia-alumina complex is prepared by impregnating 'gamma alumina ashereinafter defined With a solution of lithium salt and igniting theproduct ata temperature in excess of 600 C. The catalyst may be preparedby washing lithi'a alumina complex, crushing to granules, andimpregnating these with astlluble alcium compound capable ref thermaldecomposition to the oxide. The impregnated granules are then heated toa sufficiently' high temperatureto yield the oxide.

A typical catalyst suitable rcrusein the process of the invention wasprepared as follows. 2000 grams of gamma-alumina previously washed withdilute nitric acid and ignited at 450 6., was soaked in a solutioncomprising 907 grams or water and 527 grams of lithium nitrate trihydrate, the impregnated material was ignited at 950 C. for 15 hours andthere was obtained a crude lithia-alumina complex.

This was washed with dilute nitric acid, and then copiously with water,to dissolve unreacted lithium compounds. The product was ground to 1 sto /s" granules and these were steeped in melted calcium nitratetrihydrate until they were saturated with calcium nitrate. The steepedgranules were drained and heated at a temperature sufiiciently in excessof 561 0., the melting point of calcium nitrate, to decompose thenitrate, e. g., 750 C.

By gamma-alumina in this specification is meant the species bochmite orhydrargillite, such as may be obtained by precipitation from solublealuminium compounds e. g., by alkali, and calcination at 400 to 600 C.

Catalysts prepared in this manner are very active in the process of theinvention, and have a longer life than previously known catalysts. A

catalyst of this sort can be reactivated by calcin- I ing at about 750C., but with some, albeit small,

loss in activity. We have found that the activity of such a catalystcalcined in this manner and subsequently damped with watenanddried at450 C. is .very largely restored and that the catalyst has a longer lifethan when not so aldol condensation products which comprises bringing aketone into contact in the liquid phase at a temperature of from to 30C. with a catatreated. This method of reactivation is regarded as animportant feature of the present invention. The benefits of theinvention are well brought out by the following comparative data.

The catalyst employed was "prepared by the method described above, andcontained calcium compounds equivalent to 10% by weightof calcium oxide.(It is not known whether the active catalyst under reaction conditionscomprises calcium oxide or hydroxide or a mixture of these compounds.)

A reaction temperature of to C. and a liquid space velocity of 0.5 litreper litre of bulk catalyst volume per hour were employed. The flow ofliquid was upwardly through the catalyst.

The process of the invention is also applicable to methyl ethyl, methylpropyl, and methyl isopropyl, ketones, which yield respectively: 3-methyl heptan-3-ol-5-one and 3,4-dimethyl hexan-3-ol-5-one;4-methylnonan-4-ol-6-one and 4- methyl-B-ethyl heptan-4-ol-6-one; and2,3-6-trimethyl heptan-3-ol-5-one and 2,3,4,4-tetramethylhexan-3-ol-5-one. Similar conditions to those mentioned above aresuitable.

We claim:

1. A continuous process for the production of aldol condensationproducts which comprises bringing a carbonyl compound into contact inthe liquid phase at a moderate temperature with a catalyst comprising acalcium compound selected from calcium oxide calcium hydroxide, hy-

lyst comprising a calcium compound selected from calcium oxide, calciumhydroxide, hydrous calcium oxide and hydrous calcium hydroxide,supported on granules of a lithia-alumina complex analogous to sodiumbeta-alumina and to the spinels with a defective lattice.

3. A continuous process for the production of di-acetone alcohol whichcomprises bringing acetone into'contact in the liquid phase at atemperature of from 0 to C. with a catalyst comprising a calciumcompound selected from calcium oxide, calcium hydroxide, hydrous calciumoxide and hydrous calcium hydroxide, supported on granules of alithia-alumina complex analogous to sodium beta-alumina and to thespinels with a defective lattice.

4. A continuous process as claimed in claim 3 in which a liquid spacevelocity of up to 1 litre of acetone per litre of bulk catalyst volumeper hour and a temperature of from 10 to 25 C, are employed.

5. A continuous process for the production of aldol condensationproducts which comprises bringing a ketone selected from methyl ethylketone, methyl propyl ketone and methyl isopropyl ketone into contact inthe liquid phase at from 0 to 30 C. and at a space velocity of up to 1litre of ketone per litre of bulk catalyst volume per hour with acatalyst comprising a calcium compound selected from calcium oxide,calcium hydroxide, hydrous calcium oxide and hydrous calcium hydroxide,supported on granules of a lithia-alumina complex analogous to sodiumbetaalumina and to the spinels with a defective lattice.

6. A process as claimed in claim 1 which is operated so that thecatalyst is substantially immersed in the liquid starting material.

7. A process as claimed in claim '1 in which the catalyst is reactivatedby calcining, moistening with water and drying.

FRANCIS RICHARD CHARLTON. DENNIS ALBERT DOWDEN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,654,103 Thomson Dec. 27, 1927 2,130,592 McAllister et al.Sept. 20, 1938 2,474,440 Smith et al June 28, 1949

1. A CONTINUOUS PROCESS FOR THE PRODUCTION OF ALDOL CONDENSATIONPRODUCTS WHICH COMPRISES BRINGING A CARBONYL COMPOUND INTO CONTACT INTHE LIQUID PHASE AT A MODERATE TEMPERATURE WITH A CATALYST COMPRISING ACALCIUM COMPOUND SELECTED FROM CALCIUM OXIDE CALCIUM HYDROXIDE, HYDROUSCALCIUM OXIDE AND HYDROUS CALCIUM HYDROXIDE, SUPPORTED ON GRANULES OF ALITHIA-ALUMINA COMPLEX ANALOGOUS TO SODIUM BETA-ALUMINA AND TO THESPINELS WITH A DEFECTIVE LATTICE.